Route guidance devices are heretofore known which are configured to guide a route to a designated destination while being reflected with an isolated intersection at which there is the risk for a vehicle to be isolated without smoothly passing through the intersection. For example, JP2012-247315A discloses a route guidance device in which a risk value matrix is prepared for each factor feature, such as a railroad crossing and a lane decreased portion of a road, which exists in the leaving direction from an intersection. The risk value matrix gives a risk value score that indicates the possibility that the intersection can be an isolated intersection. For a search result of the route from a starting point to a destination, the route guidance device refers to the risk value matrix for each intersection on that route to obtain the risk value score and extracts, as the isolated intersection, an intersection at which the risk value score exceeds a predetermined threshold. Then, the route guidance device searches and guides a route that allows avoidance of the isolated intersection.